273 to 440 swap

what if i was to make a manifold the same as this one, you have google (new left manifold from Accurate )This is the manifold that Accurate LTD used to make but no longer do because of cost. i have a couple of buddies, one a welder, and the other a 30 year experienced muffler guy who could handle the job. is there anyone out there who has used this manifold, and would it allow p.s.. I really would like to not have to use headers or cut the fenderwalls . thanks Gerry